The concept of foraging mode provides a framework for comparative studies of hunting behavior. Each taxon is placed on a continuum whose extremes are an active, widely searching strategy, and a passive, sit and wait (ambush) strategy. These strategies have been characterized by suites of behavioral traits: ambush foragers visually scan for prey while stationary, active foragers search while moving and make greater use of chemosensation (Pianka, 1966; Regal, 1978; Huey and Pianka, 1981). Quantifications of the foraging mode continuum have employed variables like movement frequency, and percentage of time moving. In terms of number of moves per unit time, both forest birds and insectivorous lizards exhibit a foraging mode dichotomy (McLaughlin, 1989). In other words, the distribution of species along the continuum is significantly bimodal, with few species exhibiting intermediate move frequencies. Lizard species also tend to be bimodally distributed in terms of percentage of time moving (Hertz et al., 1988). Huey and Pianka (1981) discussed constraints (e.g., sensory, physiological) that could limit the evolution of intermediate strategies. Recent work confirms a strong historical component to the distribution of foraging mode and sensory emphasis among lizards (Schwenk, 1993; Cooper, 1994). In addition to historical constraints that reflect the origin of the dichotomy, current selection may also be acting to maintain it (Cooper, 1994). A selective disadvantage to an intermediate foraging mode has not been documented, but can be logically postulated. Huey and Pianka (1981) identified the phenomenon of foraging mode switching across trophic levels-actively foraging lizards were vulnerable to sit and wait predators, and vice versa. An intermediate foraging mode might be selected against if, for example, it entailed susceptibility to both active and ambush predators. Although the basic polarization of foraging behavior remains robust (Cooper 1994), suggestions of intermediate or alternative strategies have accompanied the characterization of a dichotomy (Regal, 1978; Tollestrup, 1980; Huey and Pianka, 1981; Magnusson et al., 1985; Pietruska, 1986; Kingsbury, 1989; O'Brien et al., 1990). One potential way to reconcile these perspectives is to consider mixed strategies. A species unconstrained by sensory systems and physiology could exhibit a mixture of active and passive tactics, thereby also avoiding any selective disadvantages of intermediate behavior. Cooper's (1994) review of foraging modes indicated that, although mixed strategists had not been explicitly examined, there were suggestions of their presence in certain families (e.g., Gekkonidae, Scincidae). Such a mixed foraging strategy in the species repertoire could be manifested as variation between relatively stereotyped age, size or sex classes, or populations. Alternatively, each individual might use a mixture of tactics, either within a bout or between bouts in different circumstances. Helfman